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From: Marek Szyprowski <m.szyprowski@samsung.com>
To: linux-kernel@vger.kernel.org
Cc: Marek Szyprowski <m.szyprowski@samsung.com>,
	Matthew Garrett <mjg59@google.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	James Morris <jmorris@namei.org>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	linux-security-module@vger.kernel.org, linux-api@vger.kernel.org,
	Matthew Garrett <matthewgarrett@google.com>
Subject: [PATCH] tracefs: Fix NULL pointer dereference when no lockdown is used
Date: Wed, 14 Aug 2019 08:12:37 +0200	[thread overview]
Message-ID: <20190814061237.17406-1-m.szyprowski@samsung.com> (raw)
In-Reply-To: <3028ed35-3b6d-459f-f3c8-103c5636fe95@samsung.com>

Commit 757ff7244358 ("tracefs: Restrict tracefs when the kernel is locked
down") added infrastructure for restricting tracefs access when lockdown
is enabled. It however broke tracefs operation when no lockdown is used.
Fix this issue by adding missing check for a NULL ->open() callback.

Fixes: 757ff7244358 ("tracefs: Restrict tracefs when the kernel is locked down")
Reported-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 fs/tracefs/inode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index 12a325fb4cbd..8efff7603032 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -43,7 +43,7 @@ static int default_open_file(struct inode *inode, struct file *filp)
 		return ret;
 
 	real_fops = dentry->d_fsdata;
-	return real_fops->open(inode, filp);
+	return real_fops->open ? real_fops->open(inode, filp) : 0;
 }
 
 static ssize_t default_read_file(struct file *file, char __user *buf,
-- 
2.17.1


  parent reply	other threads:[~2019-08-14  6:12 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-31 22:15 [PATCH V37 00/29] security: Add support for locking down the kernel Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 01/29] security: Support early LSMs Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 02/29] security: Add a "locked down" LSM hook Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 03/29] security: Add a static lockdown policy LSM Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 04/29] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-08-01 14:21   ` Jessica Yu
2019-08-01 20:42     ` Matthew Garrett
2019-08-08 10:01       ` Jessica Yu
2019-08-08 18:31         ` Matthew Garrett
2019-08-08 22:43           ` James Morris
2019-08-09 20:59         ` [PATCH V39] " Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 05/29] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 06/29] kexec_load: Disable at runtime if " Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 07/29] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 08/29] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 09/29] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 10/29] hibernate: Disable when " Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 11/29] PCI: Lock down BAR access " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 12/29] x86: Lock down IO port " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 13/29] x86/msr: Restrict MSR " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 14/29] ACPI: Limit access to custom_method " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 15/29] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 16/29] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 17/29] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 18/29] Lock down TIOCSSERIAL Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 19/29] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-08-01 16:19   ` Jessica Yu
2019-08-01 20:44     ` Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 20/29] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 21/29] Lock down /proc/kcore Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 22/29] Lock down tracing and perf kprobes when in confidentiality mode Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 23/29] bpf: Restrict bpf when kernel lockdown is " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 24/29] Lock down perf when " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 25/29] kexec: Allow kexec_file() with appropriate IMA policy when locked down Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 26/29] debugfs: Restrict debugfs when the kernel is " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 27/29] tracefs: Restrict tracefs " Matthew Garrett
     [not found]   ` <CGME20190813061053eucas1p1b6945259d9663b743e7cb32521d041e7@eucas1p1.samsung.com>
2019-08-13  6:10     ` Marek Szyprowski
     [not found]       ` <CGME20190813072111eucas1p2b87f3f8d16c22a0a3d024bc5ebcc8bcc@eucas1p2.samsung.com>
2019-08-13  7:21         ` Marek Szyprowski
     [not found]           ` <CGME20190814061246eucas1p128cae99a14f27bc79fa2aa72084a0413@eucas1p1.samsung.com>
2019-08-14  6:12             ` Marek Szyprowski [this message]
2019-07-31 22:16 ` [PATCH V37 28/29] efi: Restrict efivar_ssdt_load " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 29/29] lockdown: Print current->comm in restriction messages Matthew Garrett

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